Abstract: Copper (Cu2+), a component of the mitochondrial electron transport chain which also functions in iron absorption, mobilization and in maintenance of brain neurotransmitter levels, is well known to generate cytotoxic reactive oxygen species (ROS). The aim of this study was to test a sensitive, simple and low cost enzymatic method based on the urease inhibition by very low concentrations of copper and to use this technique to study the protective effect of phytic acid against copper ions. In this way, an enzymatic method based on the ability of urease to be inhibited by very low concentrations of copper ion was utilized. Inhibition curves showed that copper (0.79 and 1.57 μ M) promoted a 43.82 ± 2.72 and 71.84 ± 6.29% inhibition of the enzyme activity, respectively. Enzyme inhibition by the same copper concentrations in the presence of phytic acid (10 mM) were markedly lower. In conclusion, phytic acid has a copper chellating capacity that may be useful in preventing copper interaction with biomolecules and, accordingly, in lowering the generation of ROS.